The present invention relates to a semiconductor device and method of manufacture thereof, a circuit board, and an electronic instrument.
Conventionally, as a semiconductor device is known one having a substrate (interposer) on which an interconnect pattern is formed, with a semiconductor chip mounted on the interposer. With the miniaturization and increasing pin count of semiconductor devices, even finer interconnect patterns are required, but there is a limit to the degree to which an interconnect pattern formed on a single interposer can be made finer. Moreover, a multilayer substrate is expensive.
By using a plurality of interposers, higher pin counts can be supported. For example, a stack type of semiconductor device has been developed, having a construction in which a plurality of interposers is adhered together, with a semiconductor chip mounted on one surface or both surfaces.
As a published example, Japanese Patent Publication number 2870530 discloses interconnect patterns formed on upper and lower interposers connected together electrically by bumps. However, by reason of this, there is the problem that the formation of bumps takes time and incurs a cost.
The present invention is made so as to solve the above problem, and has as its object the provision of a semiconductor device having a simple construction and having substrates electrically connected and a method of manufacture thereof, a circuit board, and an electronic instrument.
(1) A semiconductor device of the present invention comprises:
a plurality of substrates disposed to be stacked one another, an interconnect pattern being formed on each of the substrates; and
a semiconductor chip mounted on at least one of the substrates,
wherein the interconnect pattern has a bent portion projecting from a surface of each of the substrates, and
wherein two or more the bent portions are provided on two or more the substrates respectively, the two or more the bent portions being stacked one another and electrically connected.
According to the present invention, the bent portion is formed as a part of the interconnect pattern projecting from the surface of the substrate, and is of a simple construction. Since electrical connection between the two or more the substrates is achieved by means of the bent portions, it is not necessary to form bumps.
(2) In this semiconductor device:
a projecting surface of one of the bent portions and a depressed surface of another of the bent portions may be facing each other and electrically connected.
(3) In this semiconductor device:
the projecting surface of the one of the bent portions may enter an interior of the depressed surface of the other of the bent portions.
By means of this, the projecting surface of the one bent portion enters inside the depressed surface of the other bent portions, whereby both are accurately positioned. In accordance with the positioning of the bent portions, the substrates are also accurately positioned.
(4) In this semiconductor device:
the interior of the depressed surface of the other of the bent portions may be filled with a conductive material.
By means of this, the projecting surface of the one bent portion and the depressed surface of the other bent portion can be electrically connected by the conductive material.
(5) In this semiconductor device:
the projecting surfaces of two of the bent portions may be facing each other and electrically connected.
By means of this, the projecting sides of the bent portions are electrically connected together, as a result of which a wide spacing between the pair of substrates on which the two are provided can be obtained.
(6) In this semiconductor device:
the two or more of the bent portions, which are stacked each other and electrically connected, may have substantially the same shape.
(7) In this semiconductor device:
a penetrating hole may be formed in one of the substrates, and at least one of the bent portions may enter the penetrating hole, and
the one of the bent portions entering the penetrating hole may be a part of the interconnect pattern formed on the substrate having the penetrating hole.
By means of this, the interconnect pattern is formed on the side of the substrate opposite to that on which the bent portion projects. As a result, one of the substrates intervenes between a pair of electrically connected interconnect patterns. Therefore a short-circuit between the two can be prevented.
(8) In this semiconductor device:
in one of the substrates, penetrating holes may be formed, and at least one of the bent portions may be formed over the penetrating hole without entering the penetrating hole, and
the one of the bent portions positioned over the penetrating hole may be a part of the interconnect pattern formed on the substrate having the penetrating holes.
By means of this, because the bent portion projects on the side of the substrate on which the interconnect pattern is formed, the bent portion can be formed higher from the surface of the substrate.
(9) In this semiconductor device:
two or more the bent portions may be formed over the penetrating hole.
By means of this, for two or more bent portions only one penetrating hole need to be formed.
(10) In this semiconductor device:
two or more the penetrating holes may be formed in one of the substrates,
two or more the bent portions may be formed on the interconnect pattern formed on the one of the substrates having the two or more the penetrating holes, and
one of the bent portions may be formed over one of the penetrating holes.
By means of this, the material of the substrate intervenes between adjacent bent portions provided on one substrate. Therefore, a short-circuit between the bent portions can be prevented.
(11) A circuit board of the present invention has the above described semiconductor device mounted thereon.
(12) An electronic instrument of the present invention has the semiconductor device.
(13) A method of manufacturing a semiconductor device of the present invention comprises: mounting a semiconductor chip on at least one of a plurality of substrates, each on which an interconnect pattern is formed; disposing the substrates so as to stack one an other; and electrically connecting two or more the substrates,
wherein the interconnect pattern has a bent portion projecting from a surface of each of the substrates, and wherein two or more the bent portions are provided on two or more the substrates respectively, the two or more the bent portions being stacked one another and electrically connected.
According to the present invention, the bent portions are formed as a part of the interconnect pattern projecting from the surface of the substrate, and are of a simple construction. Since electrical connection between two or more substrates is achieved by means of the bent portions, it is not necessary to form bumps.
(14) In this method of manufacturing a semiconductor device:
a projecting surface of one of the bent portions and a depressed surface of another of the bent portions may be facing each other and electrically connected.
(15) In this method of manufacturing a semiconductor device:
the projecting surface of the one of the bent portions may enter an interior of the depressed surface of the other of the bent portions.
By means of this, the projecting surface of the one bent portion enters inside the depressed surface of the other bent portion, whereby both can be accurately positioned. In accordance with the positioning of the bent portions, the substrates can also be accurately positioned.
(16) This method of manufacturing a semiconductor device may further comprise:
filling the interior of the depressed surface of the other of the bent portions with a conductive material.
By means of this, the projecting surface of the one bent portion and the depressed surface of the other bent portion can be electrically connected by the conductive material.
(17) In this method of manufacturing a semiconductor device:
the projecting surfaces of two of the bent portions may be facing each other and electrically connected.
By means of this, the projecting sides of the bent portions are electrically connected together, as a result of which a wide spacing between the pair of substrates on which the two are provided can be obtained.
(18) In this method of manufacturing a semiconductor device:
at least one of pressure and heat may be applied to the stacked two or more the bent portions for electrical connection.
By means of this, the electrical connection of the two or more bent portions can be carried out simply.